Duplicating band



Feb. 27, 1940. J. BJoRKsTEN DUPLICATING BAND Filed Jan. 51,1958

Patented Feb. 27, 1940 UNITED STATES DUPLICATING BAND Johan Bjorksten, Chicago, Ill., assignor to Ditto,

Incorporated, Chicago, Ill., a corporation of West Virginia Application January 31, 1938-, Serial No. 187,810

- 3 Claims.

The invention relatesto hectograph pads, bands or rolls 'which usually comprise aflexible backing member having a coating lof gelatinous material to which the master sheets are first applied and to which the copy sheets are subsequently applied to duplicate data or designs received by the ,gelatinous material from the master sheets.

It has been the general practice to provide backing sheets of organic origin, such as, for example, papers or'textile fabrics. Among the disadvantages inherent in such material are greatly decreased mechanical strength when-wet, lack of uniformity in strength, great sensitivity to atp mospheric conditions, particularly humidity, neci essity of. highly complex and time consuming treatments, -highinflammability, and, where a drying oil is used as an agent for bonding the gelatinuous mass to the backing sheet, danger of l self-ignition.

The invention contemplates a hectograph blanket or roll comprising a flexible backing sheet of inorganic material not having the above enumerated disadvantages.

Several forms of the invention are embodied in hectograph rolls or bands which employ a thin flexible metal sheet as a backing. The backing Isheet is preferably aluminum and is preferably -.002 inch thick. T he gelatinous mass is secured -to Athe backing sheet by a bonding agent which may also contain dye absorbing agents to clear the gelatinous mass.A If so desired, the bonding agents vand the dye absorbing agents may be applied as separate films or coatings to the backing sheet. In some instances, the metallic backing sheets .have their edges folded to prevent tearing thereof. The backing sheets may also be corrugated to add to their strength.

Other objects-and advantages will become apparent as the following detailed description progresses, reference being had to the accompanying drawing, whereinl Figs. l'to 6, inclusive, are fragmentary perspective views of hectograph bands which embody ldifferent forms of the invention. j

Referring for the present trated, the referencel character II designates a Y backing sheet of a hectograph band which is designated generally by the reference character I0. vThe backing sheet II is preferably formed of aluminum and is preferably about .002 inch thick. 1 Applied to one surface of thebacking sheet II is a coating or film I2 which forns a ,bonding agent u to cause a gelatinous coating 3 to be bonded to to Fig. l wherein aA preferred embodiment of the invention is illusthe backing sheet II. The gelatinous coating I3 is preferably of the type commonly employed in the hectograph process. The film or coating I2 preferably is or comprises a protein precipitant4 capable of adhering to the metal surface. Such coatings are, for example, fish oil, linseed oil and cellulose lacquers containing protein precipitants such as, for example, formaldehyde, aldol or chromalum. ATo increase the clearing properties of the lm or coating I2, it also contains preferably dye absorbing agents in solution or suspension, or it may be superimposed` onl a film of such dye absorbing or neutralizing agents. Such dye absorbents are, for example, many colloids such as cellulose derivatives, resins, particularly when plasticized with dye solvents, silica gel, bentonite, ground wood pulp, wood powder and the like.' These dye absorbers or neutralizers will assist in clearing the duplicating lm after use, by binding and thus removing dyestuifs from the film.

. The back sideof the backing sheet I I is preferably coated with a film I5 of dye removing agents, such as described above, which agents will assist in removing the dye from the duplicating film against the surface of which the back side of the backing is pressed when the hectograph band III is wound into a roll.

Referring nowto Fig. 2v wherein another embodiment of the invention is disclosed, the reference character designates generally a hectograph band which comprises a backing sheet 2I" preferably formed of aluminum about .002 inch thick. Applied to the opposite sides of the backing sheet 2| are coatings or yfilms 22 and 23 which preferably comprise dye removing `agents of the type described above. Applied to the film or coating 22 is a film gr coating 24 for bonding a gelatinous coating 25 Vto the backing sheet 2I. The bonding coating 24 preferably comprises protein precipltants as defined above. Of course, the films 24 and 22 may be permitted to intermingle so that the final result is substantiallyl the same as that described in connection with Fig. 1 wherein the coating I2 contains both bonding and dye removing agents.

Referring now to Fig. 3 wherein another form of the invention is illustrated, the reference char- ",acter designates generally a hectograph band which comprises a gelatinous coating of the type usually employed in the hectograph process.

I'he gelatinous coating 25 is bonded to a backing sheet 3| which is preferably formed from aluminum about .002 inch thick. The backing sheet 3| is preferably in the form of a perforate sheet'having a plurality of relatively large perforations Ila u therein. A coating 32 interposed between the The backing sheet 40 is preferably provided Witha plurality of corrugations 4Ia extending trans- -versely thereof to strengthen the sheet. Applied to one surface of the backing sheet 4I is a coating 42 which preferably comprises the same materials as the coating I2 described above and has the same functions. The coating 42 bonds a gelatin coating 45 to the backing sheet 4I and as it preferably contains dye absorbingI agents, it assists in clearing the gelatinous mass after use.

Fig. 5 illustrates still another, form of the invention. The `reference character designates generally a hectograph band of which a portion is shown in Fig. 5. The' hectograph band 50 comprises a backing sheet 5I which is formed of metal, preferably aluminum, the sheet being preferably about .002 inch thick. The longitudinal edges of the backing sheet 5I are folded as indicated at 52 in Fig. 5 to give strength to the longitudinal edges so that they will not tear readily. Applied to the backing sheet 5I isa coating 52 which is preferably formed from the same materials as the coating I2 described above and has the same functions. The coating 52 bonds a gelatinous coating 53 to the backing sheet 5I and the dye absorbing agents in the coating 52 assist in clearing the gelatine after it has been used in the hectograph process.

1n Fig. 6, a form of the invention is shown in a hectograph band 60 which comprises a metallic backing member 6I and a gelatin lm or coating 64 of the type commonly employed in hectograph bands. The backing member 6I is preferably a mesh or screen which may be formed from thin metallic ribbons or may be formed as a wire mesh, the mesh being attened as by rolls to atten the individual wires. A coating 62 is applied to at least one side of the mesh, that is the side to which the gelatin coating 64 is applied. The film or coating' 62 is.pref

erably formed of the same materials as the coating I2 described above and bonds the-gelatin 64 to the mesh. The dye absorbing-materials in the coating 62 assist in clearing the gelatinous mass64 after it has been used.

The mesh 6I, if formed from ribbons, is pref# erably formed from thin aluminum strips.

An advantage of bonding metallic backing sheets of the kind described is that it may be subjected to high temperature without injury while in the use of paper or cloth backing sheets,

Mcare must be taken so that they will not be injured by high temperatures whenthey` are coated with lacquers, etc., and the lacquer is dried by subjecting it to heat.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims, in which it is-my intention to claim all -novelty inherent in my invention as broadly as permissible, in view of the prior art.

I claim: z 1. In a hectograph band capable of being Wound into a roll, the combination of a thin iiexible .backing sheet of non-absorbent material, coating means covering one face of said backing sheet and comprising an effective proportion of dye absorbent material for expediting the clearing of the band for repeated use, and a layer of gelatinous material bonded effectively to said first-named coating and of comparatively much greater thickness than that of ythe backing sheet which is made o"f substantially the minimum thickness consistent with the re'- quired strength.

2. `In a hectograph band capable of being wound into a roll, the combination of a thin exible-backing sheet of non-absorbent material, coating means covering one face vof said backing sheet and comprising lan effective proportion of dye absorbent material for expediting the clearcopy mass bonded effectively to said rst named coating and a coating covering the other face of said backing sheet and comprising an effective proportion of dye absorbent material for assisting in the clearing operation preparatory for a repeated use of the band.

3. In a hectograph band capable of being Wound into a roll, the combination of a thin `flexible backing sheet of aluminum, coatings. covering both faces of saidbacking sheet each comprising an 'effective proportion of dye absorbent material, a third coating covering one of said flrst-named two coatings and comprising an effective proportion of protein precipitant material adapted effectively to bond said second coating to the face of the metal backing sheet so as to permit exing of the completed band on a comparatively small radius Without danger of breaking the bond, and a coating of gelatinous material bonded eectively to said third coating and of comparatively much greater thick-v ness than that of the backing lsheet which is made of substantially the minimum thickness JOHAN BJ ORKSTEN. 

